There exists a wide variety of different types of wireless cellular communication networks, and further types are emerging e.g. through various standardization efforts. Examples of such wireless cellular networks are GSM (Global System for Mobile communications) networks, different CDMA (Code-Division Multiple Access) networks, such as WCDMA (Wideband CDMA) and CDMA2000 networks, and 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) networks.
As the number of different wireless cellular networks increase, as well as the geographical coverage of the wireless cellular networks, the energy consumption of radio base station becomes more crucial. Accordingly, there is a need for saving energy in radio base stations.